FIG 5.

Glutamate-1-semialdehyde-2,1-aminomutase (GsaM). (A, left) Crystal structure of T. elongatus GsaM. (Right) In the active site of Synechococcus GsaM, the inhibitor gabaculine was observed to bind covalently to the PLP cofactor (m-carboxyphenylpyridoxalamine [mCPP]). (Adapted from reference 14.) (B) Depending on the initial form of the pyridoxal phosphate cofactor, GsaM is able to convert GSA into ALA via either DAVA or DOVA (4,5-dioxovalerate) (see the text for a detailed explanation). Kinetic and other biochemical data suggested that formation via DAVA is used by the enzyme. (Adapted from reference 77.)